Research On The Ecological Variation Of Vegetation And Its Influence Factors In Ningxia Municipality Based On Remote Sensing Data

The Ningxia Hui Nationality Autonomous Region locates the upriver YellowRiver, adjoining the Inner Mongolia Autonomous Region, Gansu Province, ShanxiProvince. The Yinchuan Plain takes on the advantage of agricultural development asone of the commodity grain bases. However, Ningxia lies in the northwest arid regionand the groundwater is contaminative, which has severely affected the growth in thenational economy. Therefore the research on the long-term variety of the environmentof the Ningxia Province is especially essential.The vegetation possesses the character of annual changes and seasonal varietiesand is the bond of the soil, atmosphere and moisture. The Vegetation Index thatindicates the variability regulation of vegetation eco-environment in some way is theconstitution of the linear and nonlinear combination of the multispectral data. TheNDVI (Normalized Difference Vegetation Index) quantificationally shows thevegetation energy, which is the ratio of the sum and the difference of the infraredspectral and visible red spectral.With the development of the remote sensing (RS), the dynamic inspect of thevegetation area comes true. There're two major superiorities of the RS data: (1) TheRS data of satellites provides many characteristic information of the vegetation, forexample seasonal information, the ability of photosynthesis. (2) It's short-period,widespread, low-cost, wide-range and long time series.This paper studied the variability trend of NDVI from 1982 to 2004 in Ningxiaarea by using GIMMS NDVI (resolution ratio:8km) data and MODIS data(resolutionratio:250m). According to the trend line we can simulate the variability trend byanalyzing 432 images of GIMMS NDVI data between 1982-1999 and 121 images ofGIMMS data between 2000-2004 and compare them.According to the result, the variability trend of NDVI in most areas has beenascending from 1982-1999. However, due to less water resources coming from YellowRiver, the NDVI became descending after 2000.